1. Field of the Invention
The present invention generally relates to a jig for testing a circuit board. More particularly, the present invention relates to a jig which is provided with a working plate for positioning a circuit board thereon easily and smoothly, and the life of probes can be estimated by a counter detecting the times of the movement of the working plate during the testing process.
2. Description of the Related Art
Traditionally, a jig 100 for testing a printed circuit board 10, as shown in FIG. 1, comprises a base body 110, a plurality of through holes 123 and probes 123P, pins 150 and guide bars 160, and a connector 140.
The base body 110 is composed of a top plate 111, a bottom plate 112 and side plates 113, wherein the side plates 113 are arranged between the top plate 111 and the bottom plate 112. In general, the bottom plate 112 is detachably mounted on the lower surface of the side plates 113 by screwing the bolts (not shown in FIG. ) thereon so as to proceed the maintenance in the jig 100. On the top plate 111, through holes 123 are formed thereon and fitted with the probes 123P therein. The sites of the probes 123P correspond to the places in the vicinity of the soldering points of the circuit board 10, and therefore the tip of the probes 123P are touched upon the metal portion of the circuit board 10 so as to proceed the testing process, and a connector 140 is mounted on the side plate 113 and electrically coupled to each probe 123P. All the probes 123P are retractably installed in the base body 110 and simultaneously contact the metal portions of the circuit board 10 having the same height. For positioning the circuit board 10 properly, four pins 150 are individually installed on the upper surface 111U of the top plate 111 with respect to the holes 11 of the circuit board 10, and the bars 160 are used to guide the edges of the circuit board 10 onto the top plate 111 when the holes 11 of the circuit board 10 slide along the pins 150.
However, the circuit board 10 is easily locked between the pins 150 if the force applied to the circuit board 10 during placement on or removal from the top plate is not uniform, and therefore often halting the testing process. However, the installation of the bottom plate 112 requires that the bolts be screwed on the lower portion of the side plates 113, thus making maintenance of the interior of the jig 100 is inconvenient and inefficient. On the other hand, the wear of the probes 123P cannot be detected and renovated in time by the conventional jig 100 when the probes 123P have been used for a time. Thus, the life of the probes 123P cannot be effectively estimated by the jig 100.